P1582: CLINICAL CHARACTERISTICS AND INFECTION-RELATED OUTCOMES IN PATIENTS WITH LYMPHOID MALIGNANCIES WITH OR WITHOUT SECONDARY IMMUNODEFICIENCIES: RESULTS FROM A RETROSPECTIVE MULTI-DATABASE STUDY
Authors: M. S. Davids, J. Richter, C. Anderson-Smits, M. Kamieniak, K. Ren, M. Hull, J. Multani, D. Shah, C. Siffel
Journal: HemaSphere (2022)

Background: Patients with lymphoid malignancies are at particularly high risk of developing secondary immunodeficiencies (SID). Current guidelines do not provide an adequate framework for clinicians to identify patients at highest risk of developing SID and subsequent infections; nor do they provide clear treatment pathways once such patients are identified. Additional data in these areas may help to optimize outcomes for patients with lymphoid malignancies who experience SID. Aims: To understand the demographics, clinical characteristics and burden of infection in patients with lymphoid malignancies and SID, compared with those in patients without SID. Methods: In this observational, retrospective cohort study, data were extracted from two large electronic record databases – Optum-Humedica (H-DB) and Guardian Research Network (G-DB) – for the period Oct 1, 2015 to Mar 10, 2020. This period included a 6-month pre-index period (PIP) and a 12-month follow-up period following patient identification. Patients aged ≥18 years were included if they had a confirmed diagnosis of chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL), multiple myeloma (MM) or non-Hodgkin lymphoma (NHL; H-DB only) in the PIP. Using an algorithm that included diagnosis codes, immunoglobulin G (IgG) serum levels and presence of key infections/treatments, eligible patients were stratified into two cohorts: those with SID (SID cohort) and those without SID (no-SID cohort). Patients with SID or primary immunodeficiencies in the PIP were excluded. The SID index date was defined as the first occurrence of a hypogammaglobulinemia ICD-10 code, or a record of low (<5.0 g/L) serum IgG levels. The primary outcome was severe bacterial infection over 12 months of follow-up. Secondary outcomes included overall survival (Kaplan–Meier analysis). Results: In total, 2,221 patients with SID were included (H-DB/G-DB: n=1,959/262 [25.6%/33.6% CLL or SLL, 44.4%/66.4% MM, 30.0%/0% NHL]), as were 19,141 patients without SID (H-DB/G-DB: n=17,598/1,543 [22.3%/50.2% CLL or SLL, 21.4%/49.8% MM, 56.3%/0% NHL]). Mean patient age and the proportion of men were similar in both cohorts (H-DB/G-DB SID cohort: 67.3/70.6 years, 54.8%/56.1% men; no-SID cohort: 67.9/72.2 years; 52.8%/53.6% men). At 12-month follow-up, across both databases, significantly more patients with SID had experienced ≥1 infection than those without SID (both p<0.001; Table). Bacterial infections were the most frequently reported type of infection in both databases and across cohorts (H-DB/G-DB SID cohort: 55.1%/54.6%; no-SID cohort: 24.0%/25.7%). Significantly more patients with SID experienced ≥1 severe bacterial infection than those without SID (both p<0.001); H-DB/G-DB mean (standard deviation) number of severe bacterial infections was 7.6 (9.9)/2.9 (2.7) for the SID cohort versus 5.2 (6.8)/2.4 (2.2) for the no-SID cohort (Table). The proportions of patients experiencing ≥1 hospitalization associated with infection and of those using anti-infective treatment were also significantly greater in the SID cohort than in the no-SID cohort (both p<0.001; Table). Overall survival at 24 months was lower for patients with SID (H-DB/G-DB: 76.3%/77.3% of patients alive) than for those without SID (86.9%/87.8%). Image:Summary/Conclusion: With comparable results in two large databases, this study confirms that patients with lymphoid malignancies and SID face a significantly higher burden of infectious complications and have shorter overall survival than those without SID.